The history of PISCES has its roots in the waning years of Queen Victoria, when the sun never set on the British empire, and the blood never dried.

British intelligence first attempted to harness the occult to carry out espionage in the late nineteenth century with the Delphi Project, an experiment by the Admiralty using a variety of popular psychic and ritual methods like the Tarot and dowsing to fix the position of enemy vessels. The Delphi Project produced little success and was shut down by 1896, but it spurred the efforts of Lt. Commander Frederick Ramsey, who would go on to devote his life to the study of the supernatural. The young naval officer continued the psychical research of the Delphi Project on his own, but despite several efforts by Ramsey to get the project reinstated, the Royal Navy ignored his reports and Ramsey soon found his military career stalled. He resigned from the military in 1900.

The years between 1900 and 1916 were a long odyssey for Ramsey as he exhausted his personal fortune in the search for individuals possessing psychic powers. For seven years, he travelled across the globe in this search before establishing the Ramsey Institute for Psychical Education to test gifted individuals and teach them how to perfect their abilities. Nevertheless, Ramsey only encountered seven individuals with any appreciable psychic talent.

Ramsey returned to military service in 1916, at the bequest of Captain Mansfield Cumming, the chief of the British Secret Intelligence Service, MI-6. Cumming had Ramsey create a department for psychic intelligence, the Special Reconnaisance Section, MI-13. Assembling a staff of alienists, psychologists, neurologists, and others well-versed in exotic disciplines like yoga and meditation, Ramsey used his pre-war research to have those "Talents" that exhibited psychic ability brought to England and use their powers to search for German U-Boats. These experiments soon broadened to include clairovoyance, precognition, psychometry, and telepathy, and by 1917, MI-13 had shown itself to be able to provide tangible if modest results. Nevertheless, due to the unconventional source of this intelligence, it was almost always ignored.

Cumming remained loyal to Ramsey and MI-13, and by the end of the war, the Special Reconnaisance Section grew to a staff of seventy researchers and twenty Talents, and Ramsey himself was promoted to the rank of Commander. MI-13 remained active through Cumming's patronage, but with his retirement in 1923, the funding quickly drained away. Ramsey was forced to drop all of his Talents from the payroll, but MI-13 and their research continued.

This research took a dark turn in the spring of 1925, when all of Ramsey's Talents suffered a mental collapse brought on by strange dreams of cyclopean cities sunk deep beneath the sea. Two committed suicide and five went hopelessly insane, but the others suddenly recovered after April 2. To explain this incident became the central question of Ramsey's life, and would lead him to a horrifying and perhaps fatal discovery.

Ramsey would not be alone in his search for answers, for in 1926, he made the acquaintance of Major David Cornwall. Cornwall had encountered the Mythos during the war and while serving as a military attache in Turkey, which lead to his early retirement. Ramsey convinced Cornwall to join him in MI-13, where the two men learned more of the dark secrets of the Great Old Ones. Any of Ramsey's preconcieved notions that these secrets could be explained by science were quickly dispelled. With growing horror, the two men came to see the Pacific myths of Great Cthulhu were behind the madness of 1925, and that great and terrible truths were hidden among these myths. It was this horror that Cornwall believed was the cause of the heart attack that took Ramsey's life in April 1932.

Cornwall inherited all that remained of MI-13: two research assistants and five secretaries cramped into two small offices in a rundown civil-service building in Whitehall. Even in such a reduced state, MI-13 was still considered for termination by the budget-conscious government. MI-13 was saved because, during their investigation into the Great Old Ones, Ramsey and Cornwall had developed contacts in occult circles in Germany. Some of those contacts were Ariosophists, seekers of the lost mystical knowledge of the Aryan race, and had become involved in the burgeoning Nazi movement in Germany. Through these contacts, Cornwall was able to place agents* close to the Ahnenerbe-SS, and gained enough intelligence on the Nazi Party to justify their existence.

With the outbreak of the war, MI-6 "reapportioned" the agents MI-13 had been running in Germany. MI-13 was left in a precarious position, as it could no longer use the conventional intelligence gathered by those agents to keep from being closed down. Salvation came from one of Ramsey's wartime Talents, Amanda Chalmers. On May 1, 1940, Chalmers recieved a premonition of the fall of France and the Dunkirk evacuation, and contacted MI-13 to warn them. Cornwall sent these predictions in a sealed envelope to the office of Winston Churchill, to be opened on June 5th. When the envelope was opened and the contents read, Churchill immediately became a believer in the cause of MI-13.

On June 26, 1940, the Paranormal Intelligence Section for Counterintelligence, Espionage, and Sabotage was put into existence by order of Prime Minister Winston Churchill. Created from the personnel and resources of MI-13, PISCES was to be an interagency task force between MI-5, MI-6, and SOE to exploit the "unconventional intelligence-gathering techniques" against the Axis and to determine the extent and nature of the German paranormal intelligence program. Cornwall was promoted to Colonel and report directly to Churchill alone. PISCES could approve or deny the use of their resources for MI-5, MI-6, or SOE operations, while PISCES had priority to call upon the resources of these agencies for use in their own operations. This put PISCES above the political infighting that marred British intelligence and sabotage operations throughout the war.

To escape the bombing and maintain secrecy for their unconventional operations from those in the high command less-enlightened, PISCES moved their headquarters out of London to Kilmaur Manor in the Scottish highlands. Kilmaur Manor would serve as more than the headquarters of PISCES, but also as a school for intelligence and commando training, and the site of "The Vault", a well-guarded library that would go on to house the most extensive collection of occult tomes in Europe.